1. Technical Field
The present invention relates to a method and structure for fabricating a dual damascene copper wiring interconnect contacting a damascene tungsten wiring level.
2. Related Art
An integrated circuit fabricated on a semiconductor substrate typically requires multiple levels of metal interconnections for electrically interconnecting discrete semiconductor devices on the semiconductor substrate. A lower wiring level of damascene tungsten contacts is commonly used to provide local interconnections between the semiconductor devices which exist within and upon the substrate layer. Unfortunately, it is problematic to generate reliable, low resistance contacts between an upper level of damascene copper wiring and the lower wiring level of damascene tungsten contacts.
There is a need for a method and structure that generates reliable, low resistance contacts between an upper level of damascene copper wiring and the lower wiring level of damascene tungsten contacts.